What do you use for medium-value capacitors?

[MRiddickW]

Hi all!

I'm working on fitting a boost pedal into a mini enclosure (1590A), so I'm using as much SMD as possible. The circuit has three 0.22 uF coupling capacitors. What kind of caps would you use for this when trying to save space?

PPS and PP caps are my usual go-tos, but PPS SMD caps are big and relatively expensive, and PP TH caps are big and only through-hole.

Should I just go with audio-grade electrolytics, or is there a better choice? It's doubly perplexing since they're directly in the signal path. I'm happy to post part or all of the schematic if you need context.

Thanks!

[jubal81]

I used this one recently when I needed a SMD film cap:

https://www.mouser.com/ProductDetail/80-LDECC3220JA5N00

Wima also does SMD film:
https://www.mouser.com/ProductDetail/505-SMDTD031KAKP00

[vigilante397]

I use SMD exclusively, but I'm cheap so I just use whatever I can get in the value/voltage I need and a size I like (generally 0805). Most of the caps I use are X5R or X7R ceramic.

[merlinb]

Should I just go with audio-grade electrolytics, or is there a better choice? It's doubly perplexing since they're directly in the signal path.

Ordinary electrolytics have no effect on audio, provided the cut-off frequency is well below audio frequencies.

I'm happy to post part or all of the schematic if you need context.

If you want to answer your first question then yes, we need the circuit for context.

[MRiddickW]

Here it is. C1, C2, and C4 are the caps in question.

[merlinb]

Here it is. C1, C2, and C4 are the caps in question.

Looks like C2 and C4 can be way smaller, like 22nF, since they're feeding 1M impedances. But C1 feeds the outside world so it needs to be at least as big as it currently is. You could use an electrolytic if it helps (e.g. 10uF).

[MRiddickW]

Oh, good point! That should help a lot!